I have a Li-ion battery that I pulled from a MS Band 2. It comes with a protection chip, which I am having trouble with.
The chip has 4 accessible pins, labeled "P+, K, T, P-". I've tried every combination of those 4 pins across an LED and never got any current. I am able to get power if I connect straight to the battery's terminals (B+, B-). I also discovered that I could get power out of P+ and the battery's negative terminal (B-). I've triple checked my solder, so it isn't a connection issue.
At this point, I don't know how to get power out of the protection circuit safely, nor how to charge the battery. I have yet to try hooking up K or T to an I2C, but I don't think that would help here. I know that T is most likely the temperature resistor, but I don't know how to wire that up. I don't know (and couldn't find any info on) what the K terminal is.
Please help! Thanks.